1. Field of the Invention
The invention relates to a recording apparatus for effecting recording on a recording medium by a recording head.
2. Description of Related Art
A recording apparatus having the functions of a printer, a copying machine, a facsimile apparatus, etc., or a recording apparatus used as the output apparatus of compound type electronic apparatus or a work station including a computer, a word processor, etc., has such a construction that can record an image on a recording material (recording medium) such as paper or a plastic thin sheet on the basis of image information. Such recording apparatuses can be grouped into an ink jet type, a wire dot type, a thermal type, a laser beam type, etc., depending on its recording method.
In a recording apparatus of a serial type adopting a serial scanning method of main-scanning in a direction intersecting with the conveyance direction (sub-scanning direction) of a recording material, the operation of an image being recorded (main-scanned) by recording means carried on a carriage moved along the recording material, and the conveyance (pitch conveyance) of the recording material being effected in a predetermined amount of feeding after the recording of one line has been finished is repeated, whereby recording on the entire recording material is accomplished. On the other hand, in a recording apparatus of a line type for recording by only sub-scanning in the conveying direction of a recording material, the operation of setting the recording material at a predetermined recording position, collectively effecting the recording of one line, and thereafter effecting the conveyance (pitch conveyance) of the recording material in a predetermined amount of feeding, and further collectively effecting the recording of the next line is repeated, whereby recording on the entire recording material is accomplished.
Of the above-described recording apparatuses, the recording apparatus of the ink jet type (ink jet recording apparatus) using the serial scanning method effects recording by discharging ink from recording means (a recording head) to the recording material, and has the merits that the compactness of the recording means is easy to realize, and the apparatus can record highly definite images at a high speed, can record on plain paper without subjecting the paper to special treatment, is low in running cost, suffers little from noise because it is of a non-impact type, and can easily record a color image by the use of inks of multiple colors.
Particularly, as regards the recording means (recording head) of the ink jet type utilizing thermal energy to discharge ink, by forming a film-shaped electro-thermal conversion member, an electrode, a liquid path wall, a top plate, etc. on a substrate by way of semiconductor manufacturing processes such as etching, vapor deposition and sputtering, one having a highly dense liquid path arrangement (discharge port arrangement) can be manufactured easily, and further compactness can be achieved.
In recent years, requirements for the quality of the recording material have become various, and recording not only on paper and resin sheets (such as OHP) which are ordinary recording materials, but also on thin paper and processed paper (perforated paper for filing, paper of any shape, etc.) has come to be required.
To obtain sharp-cut recording of a high quality in the above-described ink jet recording apparatus, it is very important to stabilize the behavior of the carriage in case of serial scanning.
As an ordinary carriage scanning mechanism of the serial scanning type, a carriage is slidably mounted by a guide rail and is engaged with a toothed belt passed over a pair of toothed timing pulleys, and the toothed timing pulleys are driven by a motor to thereby reciprocally scan the carriage. In a driving method by such a belt, the belt is shaken by the vibration of a motor which is a drive source for the carriage, or the belt is shaken by vibrations occurring when the toothed timing pulleys and the belt come into meshing engagement with each other. This shaking, if the carriage is firmly fixed, may sometimes be transmitted even to the recording head carried on the carriage. Also, the carriage may sometimes be vibrated by a sudden speed change during the reversal of reciprocation or during starting when the carriage is scanned. These make the behavior of the carriage unstable and therefore cause faulty printing or cause the production of noise such as the resonance of parts incorporated in the carriage.
Therefore, in the conventional construction, there is used a construction in which an elastic member is disposed between the belt or a member holding this belt and the carriage so that the degree of freedom of the carriage with respect to the scanning direction thereof may become high, thereby attenuating the vibration during the reversal of the carriage and the meshing vibration of the belt.
In the above-described example of the conventional art, however, the phase deviation between the motor, which is the drive source, and the carriage becomes great because the degree of freedom of the carriage with respect to the scanning direction thereof is made high, and as a result, the following problems arise:
(1) a reduction in response when the motor is started for the carriage scanning;
(2) the vibration of the carriage when the carriage is driven; and
(3) the deviation of the stopped position of the carriage.
The above-mentioned problems (1) to (3) not only lower the stability of the operation of the carriage, but also cause an increase in the total recording time (reduces throughput) because it becomes necessary to lower the scanning speed of the carriage in order to stabilize the operation of the carriage. Particularly, this is not suitable for the higher speed of printers in recent years, and leads to a construction in which the compatibility of the quality of recorded images and the recording speed is difficult.